Digital Broadcast Receiver Equalization for Mobile VSB Reception
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Solution Overview
Problem
Digital broadcasting receivers using the Vestigial Sideband (VSB) transmission mode face performance deterioration in poor channel environments, especially when mobile, due to reduced resistance to channel changes and noise.
Innovation Solution
A digital broadcasting receiver and method that processes mobile service data and main service data by configuring a Reed Solomon (RS) frame with signaling information, including a table describing the second service data, and uses known data sequences for demodulation and channel equalization, enhancing reception stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If VSB transmission mode is used for digital broadcasting, then the system can be implemented with single carrier method, but the receiving performance deteriorates in poor channel environments and mobile conditions
Solution Approach 1:
The transmission system is segmented into multiple carriers (OFDM structure) instead of using a single carrier VSB method. This divides the frequency spectrum into numerous orthogonal subcarriers, each capable of independent modulation and error correction, thereby improving robustness against channel fading and noise while maintaining implementation feasibility through standardized multi-carrier processing
Solution Approach 2:
The patent employs composite error correction coding schemes combining convolutional codes, Reed-Solomon codes, and LDPC codes in a hierarchical structure. This multi-layered error protection approach provides enhanced reliability for mobile reception by addressing different types of channel errors through complementary coding techniques
2Device complexity
If VSB transmission mode is used, then the system structure is simplified, but resistance to channel changes and noise is insufficient for portable and mobile receivers
Solution Approach 1:
The system implements dynamic adaptive modulation and coding schemes where transmission parameters (modulation order, code rate, pilot density) are adjusted based on channel conditions detected through pilot signals. This allows the system to optimize performance in real-time for mobile environments while maintaining a relatively simple base structure that can operate in fixed conditions
Solution Approach 2:
Pilot signals are introduced as intermediary reference signals embedded within the data transmission. These pilots serve as mediators between the transmitted signal and the receiver's channel estimation process, enabling accurate equalization and compensation for channel changes without requiring complex blind adaptation mechanisms
3Ease of operation
If standard VSB reception is used, then the receiver design is straightforward, but receiving performance deteriorates in mobile environments with channel distortions
Solution Approach 1:
The receiver performs preliminary channel estimation and equalization using known pilot signals before actual data demodulation. This preliminary action prepares the receiver by establishing channel characteristics and compensation filters in advance, enabling reliable data reception despite mobile channel distortions while keeping the overall design systematic and manageable
Data Source
AI summary
A method of processing broadcast data includes: receiving a broadcast signal including a group including mobile service data, FIC data, TPC data and known data sequences; demodulating the broadcast signal; compensating channel distortion generated in the demodulated broadcast signal based upon at least one of the known data sequences; decoding the FIC data and the TPC data from the channel distortion compensated broadcast signal; extracting the signaling information table from the channel distortion compensated broadcast signal; identifying a stream where keys to decrypt the mobile service data are obtained using the extracted signaling information table; and decrypting the mobile service data using the keys. The group further includes data blocks. First, fourth, fifth and sixth known data sequences are inserted into third, fifth, sixth and seventh data blocks, respectively. Second and third known data sequences are inserted into a fourth data block.